Peter Foster is the Telegraph's US Editor based in Washington DC. He moved to America in January 2012 after three years based in Beijing, where he covered the rise of China. Before that, he was based in New Delhi as South Asia correspondent. He has reported for The Telegraph for more than a decade, covering two Olympic Games, 9/11 in New York, the 2004 Boxing Day tsunami, the post-conflict phases in Afghanistan and Iraq and the 2011 Fukushima disaster in Japan.

Millions have watched the video of this incident – I’m not linking to it here, it’s too distressing – and asked, why? How can this happen? And what does it say about Chinese society in 2011 that it can?

There are many answers to be gleaned from the many thousands of postings that this incident has generated on China’s online news platforms.

The first is simply legal: China’s compensation culture makes any passer-by extremely wary of getting involved, lest they get swept up into legal claims that can drain savings accounts and consume entire lives.

Such fears are not without foundation. There are indeed cases of con-men lying down in front of buses and then falsely accusing the driver, and examples of the courts wrongly ordering Good Samaritans to pay compensation after they intervened to help an injured stranger.

But if this is really the problem, then the good news is that it’s easily fixable by enacting a Good Samaritan law which offers basic immunity from civil claims to bystanders who stop to tend to the injured.

For many Chinese, however, that is only part of the story. This case involves a child, just two years old, bleeding to death on the street in front of you. Why doesn’t that move the passers-by emotionally, overcoming their rational fear of being wrongly hit up for compensation?

It doesn’t really make sense. And in any case, if we’re being strictly rational, then a pedestrian or a cycle-rickshaw driver should hardly fear being accused of inflicting injuries on a child who has clearly been run over by a large car.

It’s also been widely noted that, compensation fears aside, the 18 passers-by didn’t even stop to phone China’s equivalent of 999 or 911 before carrying on home, many presumably to their own families, some perhaps even to their own two-year-old daughters.

Which is why, I suspect, so many Chinese people have rushed to frame this episode in moral terms.

Many posts lament the absence of moral compass in Chinese society, wondering whether the stampede to get rich these last few decades has left the moral fabric of Chinese society tramped into the dust.

Ultimately that’s for the Chinese to judge, but I wonder if this walk-on-by mentality (which I don’t believe you would see in Britain, for all the West’s moral decay) is partly a symptom of different cultural rather than moral values.

At the risk of gross generalization, in China charity really does start at home, which means that Chinese people will do far more to support their families – the aged parents, the poor sibling – than the vast majority of us Westerners ever would.

But outside that tight-knit family unit, it seems to outsiders that that there is perhaps far less obligation to do good by strangers, or attend to the common cause. It is a kind of socio-cultural equivalent of China’s national policy of ‘non-interference’.

I don’t think this excuses the fact that 18 people saw fit to leave that girl to die, but it might explain partly why they did.